Scenario

Jacob Weaver is a contractor operating as a sole proprietorship (EIN 99-3456789).

• 2014 net income: $133,000.
• Clients owe him a total of $53,000 for work completed in 2014.
• 2014 estimated tax payments: $18,000.
• He is using a bedroom in his house as a home office. The room is 15' x14'.
• He has one half-time employee, Martin, who had been unemployed since returning from Afghanistan and is disabled.
• Martin worked for Jacob for 20 hours a week, for 41 weeks of 2014.
• Martin earned $10,500.
• Jacob had to spend $7,350 for disabled access equipment for Martin.

I would like to know how to determine what the total gross income is for completing a 2014 Schedule C, as well as how to take into consideration the Estimated tax payments. I believe that I am supposed to add the $53,000 to the net income as well as the $18,000 to get the Gross income...but I am having a hard time finding evidence on substantiating the answer.